The largest fish that I've taken with a bow, was a 13 lb. carp and it was in the Clear Fork river...about 2 miles south of the Pleasant Hill dam.
Seems like any fish under 5 lbs. will just thrash around, after being stuck. However, anything over the 6 to 8 lb. range, you'll see your arrow...

Had this one sent to me in an email, just thought it was pretty interesting stuff to think about....
In WWII, Japan's highest ranking naval officer was Isoruku Yamamoto. Although he was Japanese, and his loyalties were unquestionably with The Empire, he studied for many years in America...